<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>


    document.write(typeof String);

    document.write(Function.prototype.constructor === Function);
    //保证他终止
    document.write(Function.prototype.__proto__ === Object.prototype);

    document.write(Object.prototype.__proto__ === null);
</script>

</body>
</html>